1. LED Power:4pcs CR2016 Cell Button.
2. 3 Light Modes:Continuous on,Slow flashing,Fast flashing(with switch to select)
3. Material:nylon
4. Size：XS/S/M/L/XL
XS width 1.5cm telescopic range 32-39cm (the battery case is silicone battery is CR2016*4)
-- Bust: S 32-40cm
-- Bust: M 38-50cm
-- Bust: L 43-60cm
-- Bust: XL 50-67cm